1. Field of the Invention
The present invention relates to novel adriamycin esters, a process for their preparation, and the uses thereof.
2. The Prior Art
U.S. Pat. No. 3,803,124, owned by the unrecorded assignee hereof, discloses the preparation of certain C-14 adriamycin esters of the formula: ##STR1## wherein R is an acyl radical of an acid selected from the group consisting of a substituted or unsubstituted, aliphatic mono- or dicarboxylic, aromatic, cycloaliphatic, arylaliphatic, heterocyclic acid having from 1 to 20 carbon atoms, the substituent being selected from the group consisting of halogens, hydroxyl, alkyl, alkoxy groups, free amino groups, mono- or dialkyl-substituted and nitro groups and from an alkyl- or aryl carbonic acid, from carbamic or alkylcarbamic acid and from sulfonic acid.
These esters of adriamycin are prepared according to said patent by reacting 14-bromo-daunomycin or one of its salts with a salt of the desired acid. More particularly, in accordance with the process of the invention, the 14-bromo-daunomycin or one of its salts such as the hydrochloride, is reacted with a compound of the formula ROM, wherein R is as defined above and M is an alkali or alkali earth metal or a quaternary ammonium radical eventually replaced by alkyl group. The reaction is carried out in the presence of an inert polar solvent, such as acetone, at the boiling temperature for a short time, or in the cold for a protracted reaction time. When the reaction is complete, the obtained product is isolated as such or is transformed into a salt of an inorganic or organic acid and purified by extraction and purification.
Said U.S. patent also discloses the preparation of 14-bromodaunomycin, which is one of the starting materials for the preparation of the novel esters of the present invention.